T-Shirt Quilt FMQ question

I am making my step-daughter a t-shirt quilt with t-shirts from concerts she has attended. Due to the large size of the entertainers pictures I had to make the blocks 18"x20" and it is a queen size quilt. I used a heavy stabilizer due to the size of the blocks. I am using Nature-Fil batting of 50% rayon from bamboo and 50% organic cotton and the backing is 100% cotton. I sewed the blocks together using a ball point needle. My question is what needle do I use to do the FMQ? Do I use a ball point or the usual needle for FMQ? What size needle would you recommend?

I would use a regular needle, because a ball point will possible move off line at times, and it is not sharp enough for free motion at all. With the heavy and thick quilt, I would use at least a jeans needle. If it is not real heavy and thick, I use a top stitch to do my free motion and never break threads or have any troubles with the FMQ.

From what I understand, the thicker the quilt, the bigger the needle. I did read (in a t-shirt quilt book) that t-shirt quilts are more challenging to quilt and that splurging on a LAQ is recommended. I am assuming you are working on a domestic machine. Several people have done it on a domestic, but it is more difficult.